Most applications communicate over a TCP or UDP port. Ports 0-1023 are usually privileged and require administrator or superuser access to bind a network socket to an IP with the corresponding port. But anything over 1024 is up for grabs. IANA (Internet Assigned Numbers Authority) can “reserve” ports for specific applications but this is only a formality; users and applications are free to use whatever port they wish.
So a look at some port numbers (1024+) and how they are used as default por